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Grégory Pakosz
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 Posted: Wed Jan 21, 2004 9:21 am Post subject: templatized templates - msvc .net 2003 bug found ?? |
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I experienced a strange problem using msvc .net 2003 along with templatized
templates
here is an example :
namespace first
{
namespace second
{
template<typename T, class U, template
class ClassA
{
public:
typedef T value_type;
typedef Foo<value_type> Foo_type;
typedef typename Foo_type::reference reference;
};
template<typename T, class U, template
template<typename BT, class BU, template class Bar>
class ClassB: private Bar<T,U,Foo>
{
public:
typedef T value_type;
typedef Foo<T> Foo_type;
typedef Bar<T,U,Foo> Bar_type;
typedef typename Bar_type::reference reference;
reference operator [] (int index);
};
template<typename T, class U, template
template<typename BT, class BU, template class Bar>
inline typename ClassB<T,U,Foo,Bar>::reference
ClassB<T,U,Foo,Bar>::operator [] (int index)
{
return 0;
}
} // namespace second
} // namespace first
i get the following error message
Compiling...
BUG.cpp
d:BUGBUG.cpp(35) : error C2244:
'first::second::ClassB<T,U,Foo,Bar>::operator`[]'' : unable to match
function definition to an existing declaration
d:BUGBUG.cpp(2 : see declaration of
'first::second::ClassB<T,U,Foo,Bar>::operator`[]''
definition
'ClassB<T,U,Foo,Bar>::reference first::second::ClassB<T,U,Foo,Bar>::operator
[](int)'
existing declarations
'first::second::ClassB<T,U,Foo,Bar>::reference
first::second::ClassB<T,U,Foo,Bar>::operator [](int)'
when i change "typedef typename Bar_type::reference reference;" to "typedef
typename Foo_type::reference reference;" the error message disappear and the
code compiles
did i miss something or is it a msvc 7.1 bug ???
thx in advance,
best regards,
Gregory
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Grégory Pakosz
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| Posted: Fri Jan 23, 2004 3:01 pm Post subject: Re: templatized templates - msvc .net 2003 bug found ?? |
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so nobody tried to compile this little sample in order to find out what's
wrong with it ?
it really seems to be a msvc namespace resolution bug
thx for any help
Gregory
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Graeme Prentice
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| Posted: Sat Jan 24, 2004 9:38 pm Post subject: Re: templatized templates - msvc .net 2003 bug found ?? |
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On 23 Jan 2004 10:01:22 -0500, Grégory Pakosz wrote:
| Quote: | so nobody tried to compile this little sample in order to find out what's
wrong with it ?
it really seems to be a msvc namespace resolution bug
|
Your code compiles with Comeau and GCC. Even without the namespaces,
VC7.1 gets the same error so it's probably just the nested template
template parameter that causes the problem. For VC7.1 you can
workaround it as below - the code compiles but is untested. Did you
know you could compile code snippets online here
http://www.comeaucomputing.com/tryitout/
In case you don't know, the Comeau compiler is EDG based and the most
compliant compiler available (and cheap) and you can get GCC for Windows
at www.mingw.org
namespace first
{
namespace second
{
template<typename T, class U, template
class ClassA
{
public:
typedef T value_type;
typedef Foo<value_type> Foo_type;
typedef typename Foo_type::reference reference;
};
template <typename T>
struct helper1
{
typedef T T1;
};
template<typename T, class U, template
template<typename BT, class BU, template
class BF> class Bar>
class ClassB: public Bar<T,U,Foo>
{
public:
typedef T value_type;
typedef Foo<T> Foo_type;
typedef Bar<T,U,Foo> Bar_type;
//typedef typename Bar_type::reference reference;
typedef typename
helper1<typename Bar_type::reference>::T1 reference;
reference operator [] (int index);
};
template<typename T, class U, template
template<typename BT, class BU, template
class BF> class Bar>
inline typename ClassB<T,U,Foo,Bar>::reference
ClassB<T,U,Foo,Bar>::operator [] (int index)
{
return 0;
}
} // namespace second
} // namespace first
int main()
{
}
Graeme
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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